source/web/cgi.c

   1 /*
   2    some simple CGI helper routines
   3    Copyright (C) Andrew Tridgell 1997-1998
   4
   5    This program is free software; you can redistribute it and/or modify
   6    it under the terms of the GNU General Public License as published by
   7    the Free Software Foundation; either version 2 of the License, or
   8    (at your option) any later version.
   9
  10    This program is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13    GNU General Public License for more details.
  14
  15    You should have received a copy of the GNU General Public License
  16    along with this program; if not, write to the Free Software
  17    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  18 */
  19
  20
  21 #include "includes.h"
  22 #include "smb.h"
  23
  24 #define MAX_VARIABLES 10000
  25
  26 /* set the expiry on fixed pages */
  27 #define EXPIRY_TIME (60*60*24*7)
  28
  29 #ifdef DEBUG_COMMENTS
  30 extern void print_title(char *fmt, ...);
  31 #endif
  32
  33 struct var {
  34         char *name;
  35         char *value;
  36 };
  37
  38 static struct var variables[MAX_VARIABLES];
  39 static int num_variables;
  40 static int content_length;
  41 static int request_post;
  42 static char *query_string;
  43 static char *baseurl;
  44 static char *pathinfo;
  45 static char *C_user;
  46 static BOOL inetd_server;
  47 static BOOL got_request;
  48
  49 static void unescape(char *buf)
  50 {
  51         char *p=buf;
  52
  53         while ((p=strchr_m(p,'+')))
  54                 *p = ' ';
  55
  56         p = buf;
  57
  58         while (p && *p && (p=strchr_m(p,'%'))) {
  59                 int c1 = p[1];
  60                 int c2 = p[2];
  61
  62                 if (c1 >= '0' && c1 <= '9')
  63                         c1 = c1 - '0';
  64                 else if (c1 >= 'A' && c1 <= 'F')
  65                         c1 = 10 + c1 - 'A';
  66                 else if (c1 >= 'a' && c1 <= 'f')
  67                         c1 = 10 + c1 - 'a';
  68                 else {p++; continue;}
  69
  70                 if (c2 >= '0' && c2 <= '9')
  71                         c2 = c2 - '0';
  72                 else if (c2 >= 'A' && c2 <= 'F')
  73                         c2 = 10 + c2 - 'A';
  74                 else if (c2 >= 'a' && c2 <= 'f')
  75                         c2 = 10 + c2 - 'a';
  76                 else {p++; continue;}
  77
  78                 *p = (c1<<4) | c2;
  79
  80                 memcpy(p+1, p+3, strlen(p+3)+1);
  81                 p++;
  82         }
  83 }
  84
  85
  86 static char *grab_line(FILE *f, int *cl)
  87 {
  88         char *ret = NULL;
  89         int i = 0;
  90         int len = 0;
  91
  92         while ((*cl)) {
  93                 int c;
  94
  95                 if (i == len) {
  96                         char *ret2;
  97                         if (len == 0) len = 1024;
  98                         else len *= 2;
  99                         ret2 = (char *)Realloc(ret, len);
 100                         if (!ret2) return ret;
 101                         ret = ret2;
 102                 }
 103
 104                 c = fgetc(f);
 105                 (*cl)--;
 106
 107                 if (c == EOF) {
 108                         (*cl) = 0;
 109                         break;
 110                 }
 111
 112                 if (c == '\r') continue;
 113
 114                 if (strchr_m("\n&", c)) break;
 115
 116                 ret[i++] = c;
 117
 118         }
 119
 120
 121         ret[i] = 0;
 122         return ret;
 123 }
 124
 125 /***************************************************************************
 126   load all the variables passed to the CGI program. May have multiple variables
 127   with the same name and the same or different values. Takes a file parameter
 128   for simulating CGI invocation eg loading saved preferences.
 129   ***************************************************************************/
 130 void cgi_load_variables(void)
 131 {
 132         static char *line;
 133         char *p, *s, *tok;
 134         int len, i;
 135         FILE *f = stdin;
 136
 137 #ifdef DEBUG_COMMENTS
 138         char dummy[100]="";
 139         print_title(dummy);
 140         d_printf("<!== Start dump in cgi_load_variables() %s ==>\n",__FILE__);
 141 #endif
 142
 143         if (!content_length) {
 144                 p = getenv("CONTENT_LENGTH");
 145                 len = p?atoi(p):0;
 146         } else {
 147                 len = content_length;
 148         }
 149
 150
 151         if (len > 0 &&
 152             (request_post ||
 153              ((s=getenv("REQUEST_METHOD")) &&
 154               strcasecmp(s,"POST")==0))) {
 155                 while (len && (line=grab_line(f, &len))) {
 156                         p = strchr_m(line,'=');
 157                         if (!p) continue;
 158
 159                         *p = 0;
 160
 161                         variables[num_variables].name = strdup(line);
 162                         variables[num_variables].value = strdup(p+1);
 163
 164                         SAFE_FREE(line);
 165
 166                         if (!variables[num_variables].name ||
 167                             !variables[num_variables].value)
 168                                 continue;
 169
 170                         unescape(variables[num_variables].value);
 171                         unescape(variables[num_variables].name);
 172
 173 #ifdef DEBUG_COMMENTS
 174                         printf("<!== POST var %s has value \"%s\"  ==>\n",
 175                                variables[num_variables].name,
 176                                variables[num_variables].value);
 177 #endif
 178
 179                         num_variables++;
 180                         if (num_variables == MAX_VARIABLES) break;
 181                 }
 182         }
 183
 184         fclose(stdin);
 185         open("/dev/null", O_RDWR);
 186
 187         if ((s=query_string) || (s=getenv("QUERY_STRING"))) {
 188                 for (tok=strtok(s,"&;");tok;tok=strtok(NULL,"&;")) {
 189                         p = strchr_m(tok,'=');
 190                         if (!p) continue;
 191
 192                         *p = 0;
 193
 194                         variables[num_variables].name = strdup(tok);
 195                         variables[num_variables].value = strdup(p+1);
 196
 197                         if (!variables[num_variables].name ||
 198                             !variables[num_variables].value)
 199                                 continue;
 200
 201                         unescape(variables[num_variables].value);
 202                         unescape(variables[num_variables].name);
 203
 204 #ifdef DEBUG_COMMENTS
 205                         printf("<!== Commandline var %s has value \"%s\"  ==>\n",
 206                                variables[num_variables].name,
 207                                variables[num_variables].value);
 208 #endif
 209                         num_variables++;
 210                         if (num_variables == MAX_VARIABLES) break;
 211                 }
 212
 213         }
 214 #ifdef DEBUG_COMMENTS
 215         printf("<!== End dump in cgi_load_variables() ==>\n");
 216 #endif
 217
 218         /* variables from the client are in display charset - convert them
 219            to our internal charset before use */
 220         for (i=0;i<num_variables;i++) {
 221                 pstring dest;
 222
 223                 convert_string(CH_DISPLAY, CH_UNIX,
 224                                variables[i].name, -1,
 225                                dest, sizeof(dest));
 226                 free(variables[i].name);
 227                 variables[i].name = strdup(dest);
 228
 229                 convert_string(CH_DISPLAY, CH_UNIX,
 230                                variables[i].value, -1,
 231                                dest, sizeof(dest));
 232                 free(variables[i].value);
 233                 variables[i].value = strdup(dest);
 234         }
 235 }
 236
 237
 238 /***************************************************************************
 239   find a variable passed via CGI
 240   Doesn't quite do what you think in the case of POST text variables, because
 241   if they exist they might have a value of "" or even " ", depending on the
 242   browser. Also doesn't allow for variables[] containing multiple variables
 243   with the same name and the same or different values.
 244   ***************************************************************************/
 245 char *cgi_variable(char *name)
 246 {
 247         int i;
 248
 249         for (i=0;i<num_variables;i++)
 250                 if (strcmp(variables[i].name, name) == 0)
 251                         return variables[i].value;
 252         return NULL;
 253 }
 254
 255 /***************************************************************************
 256 tell a browser about a fatal error in the http processing
 257   ***************************************************************************/
 258 static void cgi_setup_error(char *err, char *header, char *info)
 259 {
 260         if (!got_request) {
 261                 /* damn browsers don't like getting cut off before they give a request */
 262                 char line[1024];
 263                 while (fgets(line, sizeof(line)-1, stdin)) {
 264                         if (strncasecmp(line,"GET ", 4)==0 ||
 265                             strncasecmp(line,"POST ", 5)==0 ||
 266                             strncasecmp(line,"PUT ", 4)==0) {
 267                                 break;
 268                         }
 269                 }
 270         }
 271
 272         d_printf("HTTP/1.0 %s\r\n%sConnection: close\r\nContent-Type: text/html\r\n\r\n<HTML><HEAD><TITLE>%s</TITLE></HEAD><BODY><H1>%s</H1>%s<p></BODY></HTML>\r\n\r\n", err, header, err, err, info);
 273         fclose(stdin);
 274         fclose(stdout);
 275         exit(0);
 276 }
 277
 278
 279 /***************************************************************************
 280 tell a browser about a fatal authentication error
 281   ***************************************************************************/
 282 static void cgi_auth_error(void)
 283 {
 284         if (inetd_server) {
 285                 cgi_setup_error("401 Authorization Required",
 286                                 "WWW-Authenticate: Basic realm=\"SWAT\"\r\n",
 287                                 "You must be authenticated to use this service");
 288         } else {
 289                 printf("Content-Type: text/html\r\n");
 290
 291                 printf("\r\n<HTML><HEAD><TITLE>SWAT</TITLE></HEAD>\n");
 292                 printf("<BODY><H1>Installation Error</H1>\n");
 293                 printf("SWAT must be installed via inetd. It cannot be run as a CGI script<p>\n");
 294                 printf("</BODY></HTML>\r\n");
 295         }
 296         exit(0);
 297 }
 298
 299 /***************************************************************************
 300 authenticate when we are running as a CGI
 301   ***************************************************************************/
 302 static void cgi_web_auth(void)
 303 {
 304         char *user = getenv("REMOTE_USER");
 305         struct passwd *pwd;
 306         char *head = "Content-Type: text/html\r\n\r\n<HTML><BODY><H1>SWAT installation Error</H1>\n";
 307         char *tail = "</BODY></HTML>\r\n";
 308
 309         if (!user) {
 310                 printf("%sREMOTE_USER not set. Not authenticated by web server.<br>%s\n",
 311                        head, tail);
 312                 exit(0);
 313         }
 314
 315         pwd = getpwnam_alloc(user);
 316         if (!pwd) {
 317                 printf("%sCannot find user %s<br>%s\n", head, user, tail);
 318                 exit(0);
 319         }
 320
 321         setuid(0);
 322         setuid(pwd->pw_uid);
 323         if (geteuid() != pwd->pw_uid || getuid() != pwd->pw_uid) {
 324                 printf("%sFailed to become user %s - uid=%d/%d<br>%s\n",
 325                        head, user, (int)geteuid(), (int)getuid(), tail);
 326                 exit(0);
 327         }
 328         passwd_free(&pwd);
 329 }
 330
 331 /***************************************************************************
 332 decode a base64 string in-place - simple and slow algorithm
 333   ***************************************************************************/
 334 static void base64_decode(char *s)
 335 {
 336         char *b64 = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
 337         int bit_offset, byte_offset, idx, i, n;
 338         unsigned char *d = (unsigned char *)s;
 339         char *p;
 340
 341         n=i=0;
 342
 343         while (*s && (p=strchr_m(b64,*s))) {
 344                 idx = (int)(p - b64);
 345                 byte_offset = (i*6)/8;
 346                 bit_offset = (i*6)%8;
 347                 d[byte_offset] &= ~((1<<(8-bit_offset))-1);
 348                 if (bit_offset < 3) {
 349                         d[byte_offset] |= (idx << (2-bit_offset));
 350                         n = byte_offset+1;
 351                 } else {
 352                         d[byte_offset] |= (idx >> (bit_offset-2));
 353                         d[byte_offset+1] = 0;
 354                         d[byte_offset+1] |= (idx << (8-(bit_offset-2))) & 0xFF;
 355                         n = byte_offset+2;
 356                 }
 357                 s++; i++;
 358         }
 359         /* null terminate */
 360         d[n] = 0;
 361 }
 362
 363 /***************************************************************************
 364 handle a http authentication line
 365   ***************************************************************************/
 366 static BOOL cgi_handle_authorization(char *line)
 367 {
 368         char *p, *user, *user_pass;
 369         struct passwd *pass = NULL;
 370
 371         if (strncasecmp(line,"Basic ", 6)) {
 372                 goto err;
 373         }
 374         line += 6;
 375         while (line[0] == ' ') line++;
 376         base64_decode(line);
 377         if (!(p=strchr_m(line,':'))) {
 378                 /*
 379                  * Always give the same error so a cracker
 380                  * cannot tell why we fail.
 381                  */
 382                 goto err;
 383         }
 384         *p = 0;
 385         user = line;
 386         user_pass = p+1;
 387
 388         /*
 389          * Try and get the user from the UNIX password file.
 390          */
 391
 392         pass = getpwnam_alloc(user);
 393
 394         /*
 395          * Validate the password they have given.
 396          */
 397
 398         if NT_STATUS_IS_OK(pass_check(pass, user, user_pass,
 399                       strlen(user_pass), NULL, False)) {
 400
 401                 if (pass) {
 402                         /*
 403                          * Password was ok.
 404                          */
 405
 406                         become_user_permanently(pass->pw_uid, pass->pw_gid);
 407
 408                         /* Save the users name */
 409                         C_user = strdup(user);
 410                         passwd_free(&pass);
 411                         return True;
 412                 }
 413         }
 414
 415 err:
 416         cgi_setup_error("401 Bad Authorization", "",
 417                         "username or password incorrect");
 418
 419         passwd_free(&pass);
 420         return False;
 421 }
 422
 423 /***************************************************************************
 424 is this root?
 425   ***************************************************************************/
 426 BOOL am_root(void)
 427 {
 428         if (geteuid() == 0) {
 429                 return( True);
 430         } else {
 431                 return( False);
 432         }
 433 }
 434
 435 /***************************************************************************
 436 return a ptr to the users name
 437   ***************************************************************************/
 438 char *cgi_user_name(void)
 439 {
 440         return(C_user);
 441 }
 442
 443
 444 /***************************************************************************
 445 handle a file download
 446   ***************************************************************************/
 447 static void cgi_download(char *file)
 448 {
 449         SMB_STRUCT_STAT st;
 450         char buf[1024];
 451         int fd, l, i;
 452         char *p;
 453         char *lang;
 454
 455         /* sanitise the filename */
 456         for (i=0;file[i];i++) {
 457                 if (!isalnum((int)file[i]) && !strchr_m("/.-_", file[i])) {
 458                         cgi_setup_error("404 File Not Found","",
 459                                         "Illegal character in filename");
 460                 }
 461         }
 462
 463         if (!file_exist(file, &st)) {
 464                 cgi_setup_error("404 File Not Found","",
 465                                 "The requested file was not found");
 466         }
 467
 468         fd = web_open(file,O_RDONLY,0);
 469         if (fd == -1) {
 470                 cgi_setup_error("404 File Not Found","",
 471                                 "The requested file was not found");
 472         }
 473         printf("HTTP/1.0 200 OK\r\n");
 474         if ((p=strrchr_m(file,'.'))) {
 475                 if (strcmp(p,".gif")==0) {
 476                         printf("Content-Type: image/gif\r\n");
 477                 } else if (strcmp(p,".jpg")==0) {
 478                         printf("Content-Type: image/jpeg\r\n");
 479                 } else if (strcmp(p,".txt")==0) {
 480                         printf("Content-Type: text/plain\r\n");
 481                 } else {
 482                         printf("Content-Type: text/html\r\n");
 483                 }
 484         }
 485         printf("Expires: %s\r\n", http_timestring(time(NULL)+EXPIRY_TIME));
 486
 487         lang = lang_tdb_current();
 488         if (lang) {
 489                 printf("Content-Language: %s\r\n", lang);
 490         }
 491
 492         printf("Content-Length: %d\r\n\r\n", (int)st.st_size);
 493         while ((l=read(fd,buf,sizeof(buf)))>0) {
 494                 fwrite(buf, 1, l, stdout);
 495         }
 496         close(fd);
 497         exit(0);
 498 }
 499
 500
 501
 502
 503 /**
 504  * @brief Setup the CGI framework.
 505  *
 506  * Setup the cgi framework, handling the possibility that this program
 507  * is either run as a true CGI program with a gateway to a web server, or
 508  * is itself a mini web server.
 509  **/
 510 void cgi_setup(const char *rootdir, int auth_required)
 511 {
 512         BOOL authenticated = False;
 513         char line[1024];
 514         char *url=NULL;
 515         char *p;
 516         char *lang;
 517
 518         if (chdir(rootdir)) {
 519                 cgi_setup_error("400 Server Error", "",
 520                                 "chdir failed - the server is not configured correctly");
 521         }
 522
 523         /* Handle the possability we might be running as non-root */
 524         sec_init();
 525
 526         if ((lang=getenv("HTTP_ACCEPT_LANGUAGE"))) {
 527                 /* if running as a cgi program */
 528                 web_set_lang(lang);
 529         }
 530
 531         /* maybe we are running under a web server */
 532         if (getenv("CONTENT_LENGTH") || getenv("REQUEST_METHOD")) {
 533                 if (auth_required) {
 534                         cgi_web_auth();
 535                 }
 536                 return;
 537         }
 538
 539         inetd_server = True;
 540
 541         if (!check_access(1, lp_hostsallow(-1), lp_hostsdeny(-1))) {
 542                 cgi_setup_error("400 Server Error", "",
 543                                 "Samba is configured to deny access from this client\n<br>Check your \"hosts allow\" and \"hosts deny\" options in smb.conf ");
 544         }
 545
 546         /* we are a mini-web server. We need to read the request from stdin
 547            and handle authentication etc */
 548         while (fgets(line, sizeof(line)-1, stdin)) {
 549                 if (line[0] == '\r' || line[0] == '\n') break;
 550                 if (strncasecmp(line,"GET ", 4)==0) {
 551                         got_request = True;
 552                         url = strdup(&line[4]);
 553                 } else if (strncasecmp(line,"POST ", 5)==0) {
 554                         got_request = True;
 555                         request_post = 1;
 556                         url = strdup(&line[5]);
 557                 } else if (strncasecmp(line,"PUT ", 4)==0) {
 558                         got_request = True;
 559                         cgi_setup_error("400 Bad Request", "",
 560                                         "This server does not accept PUT requests");
 561                 } else if (strncasecmp(line,"Authorization: ", 15)==0) {
 562                         authenticated = cgi_handle_authorization(&line[15]);
 563                 } else if (strncasecmp(line,"Content-Length: ", 16)==0) {
 564                         content_length = atoi(&line[16]);
 565                 } else if (strncasecmp(line,"Accept-Language: ", 17)==0) {
 566                         web_set_lang(&line[17]);
 567                 }
 568                 /* ignore all other requests! */
 569         }
 570
 571         if (auth_required && !authenticated) {
 572                 cgi_auth_error();
 573         }
 574
 575         if (!url) {
 576                 cgi_setup_error("400 Bad Request", "",
 577                                 "You must specify a GET or POST request");
 578         }
 579
 580         /* trim the URL */
 581         if ((p = strchr_m(url,' ')) || (p=strchr_m(url,'\t'))) {
 582                 *p = 0;
 583         }
 584         while (*url && strchr_m("\r\n",url[strlen(url)-1])) {
 585                 url[strlen(url)-1] = 0;
 586         }
 587
 588         /* anything following a ? in the URL is part of the query string */
 589         if ((p=strchr_m(url,'?'))) {
 590                 query_string = p+1;
 591                 *p = 0;
 592         }
 593
 594         string_sub(url, "/swat/", "", 0);
 595
 596         if (url[0] != '/' && strstr(url,"..")==0 && file_exist(url, NULL)) {
 597                 cgi_download(url);
 598         }
 599
 600         printf("HTTP/1.0 200 OK\r\nConnection: close\r\n");
 601         printf("Date: %s\r\n", http_timestring(time(NULL)));
 602         baseurl = "";
 603         pathinfo = url+1;
 604 }
 605
 606
 607 /***************************************************************************
 608 return the current pages URL
 609   ***************************************************************************/
 610 char *cgi_baseurl(void)
 611 {
 612         if (inetd_server) {
 613                 return baseurl;
 614         }
 615         return getenv("SCRIPT_NAME");
 616 }
 617
 618 /***************************************************************************
 619 return the current pages path info
 620   ***************************************************************************/
 621 char *cgi_pathinfo(void)
 622 {
 623         char *r;
 624         if (inetd_server) {
 625                 return pathinfo;
 626         }
 627         r = getenv("PATH_INFO");
 628         if (!r) return "";
 629         if (*r == '/') r++;
 630         return r;
 631 }
 632
 633 /***************************************************************************
 634 return the hostname of the client
 635   ***************************************************************************/
 636 char *cgi_remote_host(void)
 637 {
 638         if (inetd_server) {
 639                 return get_socket_name(1);
 640         }
 641         return getenv("REMOTE_HOST");
 642 }
 643
 644 /***************************************************************************
 645 return the hostname of the client
 646   ***************************************************************************/
 647 char *cgi_remote_addr(void)
 648 {
 649         if (inetd_server) {
 650                 return get_socket_addr(1);
 651         }
 652         return getenv("REMOTE_ADDR");
 653 }
 654
 655
 656 /***************************************************************************
 657 return True if the request was a POST
 658   ***************************************************************************/
 659 BOOL cgi_waspost(void)
 660 {
 661         if (inetd_server) {
 662                 return request_post;
 663         }
 664         return strequal(getenv("REQUEST_METHOD"), "POST");
 665 }